1. Field of the Invention
The present invention relates to an image forming device and an image forming method, and in particular, to an image forming device that supplies liquid drops to plural liquid chambers from one flow path, and to an image forming method using the image forming device.
2. Description of the Related Art
In an inkjet printer that jets ink drops by raising the pressures of ink chambers, the jetted ink amounts and the jetting speeds changing due to the presence/absence of simultaneous jetting of nearby nozzles (hereinafter called “crosstalk”) is known. These are caused by the meniscus force that arises accompanying the reduction of the ink amount of the ink chamber, or by pressure waves that accompany jetting. An example of changes in jetting speed is shown in FIG. 12. One flow path, and plural nozzles that jet ink drops due to ink being supplied from the flow path are illustrated in FIG. 12. By using the black nozzle as a reference, it is shown that, the closer the distance between the nozzles, the greater then speed errors as is shown in FIG. 12.
In recent years, due to the demands on inkjet printers for increased speed, decreased electric power consumption and increased quality, attention has focused in single-pass inkjet printers using a line head at which nozzles are arrayed two-dimensionally. However, it is easy for such inkjet printers to be affected by crosstalk. At high density portions in particular, crosstalk manifests forms on the image as unevenness of density, stripe-like unevenness and jaggedness, and is a cause of deterioration in image quality.
Japanese Patent Applications Laid-Open (JP-A) Nos. 2000-218823 and 2007-237477 are proposed as techniques for suppressing unevenness of density due to crosstalk. JP-A No. 2000-218823 discloses an unevenness correcting method with respect to unevenness of density caused at the time when numerous ink drops are jetted simultaneously, i.e., with respect to the above-described problem. Among the jetting errors, with regard to errors in the drop amounts, JP-A No. 2000-218823 discloses a method of improving image quality by applying feedback to changes in the volume of an ink path.
On the other hand, JP-A No. 2007-237477 discloses a method of correcting unevenness of density that arises due to a reduction in drop amounts caused at the time when ink drops are jetted frequently from the same nozzle mainly in terms of time. In accordance with JP-A No. 2007-237477, back-pressure fluctuations are predicted from prepared print data, density fluctuations are predicted from the predicted back-pressure, and the print data is corrected on the basis of these fluctuations.
Further, there is the idea to suppress simultaneous jetting of adjacent nozzles, and JP-A No. 2003-266666 discloses a technique of suppressing simultaneous jetting of adjacent nozzles within a scan by using a mask pattern in a serial printer.
However, as disclosed in JP-A No. 2000-218823, incorporating this mechanism is related to a great increase in manufacturing costs. Further, because controlling drop amounts is generally difficult, there is the problem that unevenness of density cannot be completely eradicated.
Moreover, with the method disclosed in JP-A No. 2007-237477, even with the print data after correction, meniscus fluctuations are bound to arise, and, in order to predict the unevenness of density, prediction must be carried out again which is difficult in practice. Further, neither of JP-A Nos. 2000-218823 and 2007-237477 can address jaggedness and the like that arise due to fluctuations in speed. Also, the technique disclosed in JP-A No. 2003-266666 cannot be applied to single-pass printers.
Thus, the conventional art have the drawbacks that they cannot easily suppress image deterioration including at least one of unevenness of density, stripe-like unevenness, and jaggedness caused by crosstalk.